The times I have lived through have not been dark in the way that they were dark for Mum and Dad, who had had to put up with two World Wars, the Wall Street Crash, the Great Depression and rationing.

The Angel of the North, near Newcastle

No, they have been nothing like that.

I have never had to sit in a flimsy air-raid shelter in the back yard and watch the sky burn red as Coventry burned, thinking we would be next. (By the way, is it true, as I heard on the radio, that the British knew about the raid on Coventry before it happened, and didn’t do anything about it so the Germans wouldn’t know they had cracked the code, and does this make Churchill a war criminal, as my dad always maintained?)

I can remember the fear in the school playground as the Cuban missile crisis reached its climax, in 1962. We didn’t know what it was all about, but we could sense the fear in the grown-ups, and we stood still in the playground at the expiration of Kennedy’s ultimatum, awaiting the end of the world. I lived through all of the Cold War, always sympathetic to Moscow until the betrayal of the Russian invasion of Czechoslovakia in 1968, and I carry with me the image of the student girl, standing in front of a Russian tank on a Prague street, holding a red rose.

But, I’m not even sure of that image, anymore. In my memory she was standing alone in the middle of a snow-covered street. Was it winter? The uprising was called “The Prague Spring”, but had it lasted so long?

Did she put the rose into the muzzle of the tank, in a gesture of fragile beauty? Or am I confusing her with another photo, of a hippy girl in America offering a flower to a soldier at an anti-Vietnam War rally? Or an English girl offering a flower to a policeman at the Grosvenor Square demonstration in London in 1968?

Even with potent symbols like these, I am unsure of my ground now. It is horribly possible that my life has been manipulated by changing shapes and changing memories.

And where is she now, that girl? Has she, too, slipped between the paving slabs of history? I hope she has had children to a kind-hearted, long-haired revolutionary, and that her grandchildren have that black and white photograph of their granny defying the armoured might of the Red Army on their bedroom wall.

I have demonstrated against the civil war in Biafra, and the war in Vietnam. I marched in Hyde Park and Grosvenorr Square, and applauded the podium speeches of Tony Benn, who was, in the words of Harold Wilson, busy “immaturing with age”. (Thank goodness.)

Are the images from that time still accurate? Here is a naked girl running down a track towards the camera, screaming and burning, after an American napalm attack in Vietnam. Or was it Cambodia? Or Laos?

And here is the Vietnamese prisoner who was shot through the head by his American captor on camera, the victim’s head distorted by the bullet, like a punctured balloon.

Here are the Buddhist monks burning themselves to death on the streets of Saigon.

And here are the starving, pot-bellied babies of Ethiopia, and here are the victims of apartheid in the Sharpeville Massacre in South Africa, and here are the Disappeared in Chile, crowded into a vast football stadium.

Please stop. The list is endless.

How could these things happen and there be no ripple in the collective consciousness?

But the ripples that were set off in my mind are now beginning to criss-cross and grow confused. All these things happened, but were they exactly as my mind has reconstructed them?

Nevertheless, I must think about them. Lest I forget. For this has been my life, and these things should never happen again. Please?